1. Field of the Invention
The present invention relates, in general, to an integrated delivery system using a prefilled syringe. In particular, the present invention relates to the use of a permanently protected needle in such a system.
2. Description of the Prior Art
In the art of medical syringes, it is well known to provide a protected needle which is selectively exposed for a limited period for injection before being returned to a protected state. This protected state of the needle allows the syringe to be easily handled by medical personnel with reduced risk of accidental injury, injection and subsequent infection from an exposed needle. However, such syringes are still hazardous in that they may be mishandled by medical personnel so that a needle is inadvertently exposed leading to the possibility of such accidental injury, injection and infection.
Examples of these syringes are shown in U.S. Pat. Nos. 4,693,708 and 4,681,567. The U.S. Pat. No. 4,693,708 discloses a cylindrical housing of the needle guard which extends and retracts with respect to the syringe barrel. The U.S. Pat. No. 4,681,567 patent discloses a slidably mounted sheath which acts as a needle guard.
Moreover, it is well-known in the prior art to use a sealed hypodermic syringe. An example of such a syringe is found in U.S. Pat. No. 3,825,003.
Further, in the prior art, it is well known to use a prefilled syringe to deliver medicine or pharmaceutical product to separate medical apparatus for subsequent infusion into the patient. However, in order to be compatible with a wide range of apparatus, and possibly due to an ill-considered decision to borrow from the art of syringes which are used for direct injection into a patient (which fundamentally must provide an exposed needle to allow for direct injection), these prefilled syringes have typically included a needle which is either permanently exposed or selectively exposed.
This permanent or selective exposure of the needle leads to two disadvantages.
Firstly, the exposed needle is dangerous to medical personnel.
Secondly, the exposed needle typically has no means for guiding the needle into a small insertion area of the aforementioned separate medical apparatus. Inaccurate insertion of the needle into the medical apparatus can result in contamination of the needle, damage to the needle or to the apparatus or injury to the user. A good example of such an apparatus is disclosed in U.S. Pat. No. 4,232,669. This apparatus includes a needle which is protected by a protective sheath and a removable protective cap. In order to use this device, the cap is removed which exposes the needle beyond the protection of the detachable protective sheath.
It is therefore an object of the present invention to provide a prefilled syringe wherein the needle is permanently shielded.
It is therefore a further object of the present invention to provide a prefilled syringe which includes a means for guiding the needle accurately into other medical apparatus.